Radiator.



.L. COUHTGT.

RADIATOR.

APPLICATION FILED lAN. I3. 1914.

,239,428 Patented Sept. 4, 1917'.

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lLOUIS COURTOT, F PARIS, FRANCE, ASSIGNOR TO AMERICAN RADIATOIR, COMPANY',

OF CIICAGO, ILLINOIS, A CORPORATION 0F NEW JERSEY.y

RADIATOR.

Specication'of Letters Patent.

Application filed January 13, 1914. Serial No. 811,794.

' the following yis 'a full, clear, and exact specification.

My invention and discovery relates to 1mprovemen-ts in heating apparatus, and the same has for its object more particularly to provide a castmetalradiator formed o f a plurality of units each offwhichcomprlses a transverse connecting member or manifold and a plurality of tubes each having a wall ormetal line of predetermined thickness, and

an external diameterv so proportioned as to give a low value to the ratio of the annular cross-sectional area or the metalline relative to the external circumference or the ex ternal surface of a unit length of tube.

Further said invention has for its object to provide a radiator which has the same amount of radiating surface as the large and heavy radiators now use, but which is about one-third or more smaller, about one-third or more lighter, and yet ismaterially more efficient.

Further said lnvention has for its object to provide a cast metal radiator which may V be produced at a smaller cost per unit of radiating surface, which is more compact in ploy-in radiators of this type without imf-- pairing-theirzcapacity of resisting the pres.- sure existing within the radiator. On the contrary their capacity of Vresisting shocks and pressure is materially enhanced.

Heretofore the radiator manufacturer, in i Iaiming to increase thecapacity or eiciency of the radiator, merely increased the size of the tube, varied the shape thereof or provided the same with Ens, ribs, etc. This was done without taking into consideration either the internal diameter or the metal lineof the'tube or receptacle.'

volume and said metal line remained large in transverse area while the proportion of .the metal'line thereof relative to the external diameter of thekv tube as Well as to the unit of external or radlating surface was radiating surface.

The core entirely .unappreciated land therefore dis-l regarded.-

- In. constructing a radiator accordingto invention I form the radiator section Patented sept. 4, i917. A

with'a plurality of separated,thin-walled;

tubeswhose metal line is of such predetermined or calculated thickness, and whose external diameter is of such proportion as 1 to give a lowvalue to the ratio which vthe annular cross-sectional area or metal line unit length of tube.` By preference I form headerwhose Walls `are somewhat thicker than thewalls or metal line of saidv tube.

Now, in the course of the development of my invention, I have discovered that' in order to obtain the most e'fiicient and^eco nomical results and the greatestgeiciency per unit of radiating surface, the external diameter ofthe tube, the volume of the core and the thickness of the metal line inA relation to a unit of radiating surface should be combined in a certain vratio-or harmony in order to obtain an eiiciencyand economic result never heretofore obtainedV a radiator. 1

Further I have discovered thatvthe best results so far as eficiency are concernedare not obtained by merely increasing the area of the radiating surface, but high efficiency f is best obtained when the weight of metal employed bears a `fixed relation to a unit of Further I have found that the maximum of efficiency per unit of radiating surface may be best obtained by using a plurality `of. properly proportioned tubes of small diameter.

Further I have found that by constructing a radiator incorporatin herein set forth I am enable to reduce the costof construction materially, and yet produce a structure which overcomes the disadvantages of the cast metal type of radiator now in use, and which is in addition smaller, lighter, neater and more compact per unit of radiating surface. Further, I can-produce a radiator-which is capable of withstanding the same or greater internal pressure than the type heretofore made. The constructionA of a radiator incorporating the 'features above described permits of the features the -more accurate making of the cores. This lminimiaes the danger of shifting of the core in the processof molding, and also the displacing of the core during the operaf tion of pouring the metal, and thus insures a more uniform and a more regular line of metal-one that is materially thinner than has heretofore been possible to obtain in work of this character.

To the attainment of the foregoing objects and ends my invention consists in the novel details of construction and in the combination, connection and arrangement of parts hereinafter more fully described and then pointed out in the claims.

In the accompanying drawings forming part of this specification,'wherein like numerals .of reference indicate like parts,-

Figure 1 is a perspectiveview showing one form of radiator constructed according to land embodying my said invention;

Fig. 2 isan enlarged detail face view of a single detached radiator section;

Fig. 3 is an edge view thereof;

Fig. 4 is a transverse section taken on the line 4.-4 of Fig. 2. s

Fig. 5 is a detail vertical section taken on the line 5-5 of Fig. 2;

Figi 6 is a detail transverse section showing aV modified construction in which the tubes are connected by webs; and

' Fig. 7 is a chart of curves for dierent thicknesses of metal lines expressing the relation existing between outside diameter of tube, external surface per unit length of tube, and annular cross-sectional area or s metal line.

In said drawings 10 designates a radiator comprising ya plurality of intermediate sections 11, 11, and end sections 12, 12, which latter are .provided with supporting legs 13, 1a.

Each radiator section is formed as an integral structural unit and consists of a narrow vertical base 15, a series of small tubes 16, 16, 'which by preference in the present instance I have shown as of equal diameter having their lower ends communicating withI the interior of said base 15, and a header 17 which corresponds in outline and size with the base 15 and is formed. integrally with the upper ends of the tubes 16, 16 which communicate therewith. By preferenceI make the walls or metal line of said base and header somewhat thicker than that of said tubes in order that the same may safely withstand the pressure of the heating agent.

The tubes 16, 16 are formed with an eX- ternal diameter, ,a core volume and a metal line which bear a substantially fixed proportion or ratio to a-unit of radiating surface, which'relative proportions are readily deter-minable by means of the formula hereinbelow.

As the walls of said tubes 16, 16 possess a very thin metal line, I provide each tube preference I provide each'of said tubes upon V its outer surface with four of said longitudinal ribs 18, 18 which are arranged equally distant from each other and arrange -certain of said ribs so that their outer edges shall bein thesame vertical plane vwith the sides of said base 15 and said header 17,

As a result of extensive tests, I have found that by making the tubes 16, 16 of about 13 1n. m. inside diameter, and the Walls of said tubes about 295 m. m. in thickness a square foot of radiating surface will weigh about 3.96 pounds as comparedA with 6.50 pounds for the same radiating surface in cast metal radiators of the type now generally used, and that 'even' if the thickness ofthe tube -were not reduced a material saving of metal would still be realized perunit of radiating surface.. The proper external diameter and renders it possible to obtain this result may be readily determined by calculating the ratio existing between the .area A of the annular cross section of a round tube and the external surface-QS of a unit length the appropriate thickness of metal line Which of tube. The saidratio is proportionate to the Weight of sections having the same radiating surface.

Let D represen-t'the external diameter of the tube, e its thickness, and itis easy to ascertain or determine the ratio,-

In the chart illustrated at Fig. 7 I have plotted four curves Vwhich show the relation ofthe ratiolto the outside diameter (D) and it falls still more rapidly in proportion as the diameter'decreases; at the lower limit, z'. e., when the internal diameter becomes zero, the ratio sis reduced to 2.5,-that is to say to nearly half of what it is for external diameters between 40 and 50 n1. m.

If the thickness is 4 m. m. the ratio (as will be clear from the curve for the 4 les and the lower limit becomes 1.5.-

m. m. metal line) varies very little for diameters of 50, 4.0 and even 30 m. m. But

below 25m. m. the variation of the ratio is rapid and at the lower limit, when the internal diameter becomes zero-(outside diameter 8 m. m.), the value of is reratio-' changes from 2.55 to 2.1 for tubes of 20 and 10 m; m. diameters respectively, And if the cores and molds are adjusted with sufficient precision to reduce the thickness to 2 m. m., the above ratios for some diameters of tubes will become 1.8 and 1.6 with a lower limit of 1.0. The economy in raw material thus realized over the radiators as now made would, therefore,be more than lifty per cent.

In the modified construction shown at Fig. 6, the tubes 16a, 16a, are shown connected by integral webs'16", y16h, which form a raliator section presenting an' unbroken surace.

From the foregoing it will be noted that by means of my invention the manufacturer lis enabled to determine precisely the correct relative proportions which should exist in a radiator in order to produce the maximum eliiciency, and at the same time he is enabled toyreduce the size andy weight of the radiator about one-third or more for a given area of radiating surface, and to produce ar radiator which is neater in appearance, less expensive in construction andfmore efficient in operation than the radiators of the type now generally in` use.

f It is also to be noted that I have shown my radiatoras formed with cylindrical tubes each provided with four reinforcing ribs which project laterally but a short distance beyond the outer walls of said tubes.

1 ing pressure of the heating agent circulating within the tube and that in some instances, depending upon the shape of said tubes, said ribs may be omitted.

Further it will be obvious that my invenwill be obvious, however, that the shape of?" tion, although herein shown as applied to the well-known loop tube type of radiator' 1s, nevertheless, equally applicable to radiators of the' so-called wall type.

Having thus described my. invention, what I claim and desire to secure by Letters Patent is- 1. cast metal radiator section comprising a manifold, and a plurality of substantially cylindrical tubes in each of which the external diameter is not less than 15 m. m. and does not exceed 30 m. m., and in each of which the ratio of the annular cross-sectional area tov the external surface per unit of length does not exceed 2%, substantially as specified.

2. A cast metal radiator section Jcomprising a manifold, and a plurality of substantially cylindrical tubes in each of which the external diameter is not less than 15 mQm. and does not exceed 30 m. m., and in each of which the thickness of the metal line is not less than.1.5 m. m. and does not exceed 3 1n. m. in thickness, and in each ofA which the A ratio of thel annularrcross-sectional area to the external surface per unit of length does not exceed 22, substantially as specified.

4:. A cast metal radiator section comprising a manifold and a plurality of substantially cylindrical tubes, in which the ratio of the annular cross-sectional area to the external surface per unit of length is substan- -tially constant for tubes having an external diameter not less than 15 m. m. and not greater than 30 m. m., substantially as lspecie n v 5. A radiator section consisting of a unitary casting and comprising a manifold, and a plurality of substantially cylindrical tubes eachhaving an external diameter not less December, one thousand nine hundred and thirteen.

LOUIS COURTOT.

l Witnesses:

HANsoN C. Coxn, Mannion Roux. 

